There are a lot of factors to optimizing 3D rendering. usually there are 4 bottlenecks: CPU (creating vertices, APU calls, everything else) Bus (CPU<->GPU transfer) Vertex (vertex shader over fixed function pipeline execution) Pixel (fill, fragment shader execution and rops) Your test is giving skewed results because you have a lot of CPU (and bus) … Read more
Well, according to the OpenGL API you should use DYNAMIC_DRAW. STREAM You should use STREAM_DRAW when the data store contents will be modified once and used at most a few times. STATIC Use STATIC_DRAW when the data store contents will be modified once and used many times. DYNAMIC Use DYNAMIC_DRAW when the data store contents … Read more
Fundamentally, you need to understand two things: Vertex Array Objects (VAOs) are conceptually nothing but thin state wrappers. Vertex Buffer Objects (VBOs) store actual data. Another way of thinking about this is that VAOs describe the data stored in one or more VBOs. Think of VBOs (and buffer objects in general) as unstructured arrays of … Read more
If you have a std::vector<T> v, you may obtain a T* pointing to the start of the contiguous data (which is what OpenGL is after) with the expression &v[0]. In your case, this means passing a Vertex* to glBufferData: glBufferData( GL_ARRAY_BUFFER, vertices.size() * sizeof(Vertex), &vertices[0], GL_STATIC_DRAW ); Or like this, which is the same: glBufferData( … Read more
“Vertex Array Object” is brought to you by the OpenGL ARB Subcommittee for Silly Names. Think of it as a geometry object. (As an old time SGI Performer programmer, I call them geosets.) The instance variables/members of the object are your vertex pointer, normal pointer, color pointer, attrib N pointer, … When a VAO is … Read more